Central Aerohydrodynamic Institute
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Interview of the Deputy General Director of FSUE TsAGI, Head of the Aircraft Strength Complex, Zichenkov Mikhail by TsAGI News Magazine.

Michael Cheslavovich, what’s new in the work of the Aircraft Strength Complex in 2013?

The past year was very busy. I can say that as compared to the last year, the amount of administrative work, the number of various planning and coordination meetings, both on our internal activities and on interaction with partners, has significantly increased.

In general, we were traditionally focused on three main areas.

The first area is the research for the purpose of creating technological advances in the field of structural strength, improvement and development of our experimental base. The second area is test work and computations of specific aircraft models, individual elements, units. This includes applied research related to development, certification and operation of aircraft. And the third one is examination of various designs, materials, opinions, documents and technical solutions.

We performed an intensive large-scale work on federal target programs. These projects are codenamed “Karkas,” “Gromada,” “Ekran,” “Alaska” (which is now continued in the project “Polar Bear”), "Shatun, , “Sigma. . We took part together with other departments of the Institute in two major projects on the “Aircraft 2020” and on small aircraft.

The last year was the first year of our main work on FTP, with projects scheduled for a three-year period. In 2013, a good backlog has been created for new high-quality results. Speaking about important work, I would like to mention the creation of a new test bench and the beginning of tests of the composite fuselage model with actual dimensions, made according to mesh scheme. Introduction of composite materials in aircraft structure is associated with the search of the most promising technical solutions allowing maximizing the benefits of composites. The work is carried out in close cooperation with JSC TSNIISM (Hotkovo town), focusing mainly on space structures, as well as with European partners. We try to adapt promising space technologies to aircraft structures with account to their specific characteristics.

Another part of the research on federal programs is related to the promotion and creation of the basis for the development of normative documents in the field of strength. We carried out a number of interesting works under “Ekran” projects. As to the “Gromada” project, we got some interesting results in terms of methods and criteria of fatigue strength, as well as with regard to new promising structure condition monitoring systems.

With regard to applied research ordered by our design bureaus, we performed work on the aircraft MS-21 (or Yak-242), IL-476, Yak- 130, T −50, as well as for the development of the “Superjet” aircraft family.

Another very important subject is the work on endurance testing of the composite wing caisson prototype (together with CJSC Aerocomposite), which has passed through tens of thousands of conventional flight cycles in the laboratory. For the first time we’ve got a large amount of new experimental data, which is very important for the future of composite structures.

In addition, it is worth commenting about the completion of many years of work on resource testing of the IL-96 aircraft (together with OJSC IL), which, in particular, is used as the aircraft of our president — “Air Force One.” The tests indicated survivability, safety and reliability of the design. Despite the delays and organizational difficulties the work was completed with positive results. Survivability of the aircraft was shown, including with the presence of normalized damages that were specifically simulated on the structure.

In 2013, more than 500 conclusions were approved relating to the operation of domestic aircraft. Work on the new edition of the military strength norms is in progress. At the end of the year, we held a meeting at which the working group completed the discussion of issues related to operation of aircraft on ground conditions. It is also important to note that our complex took an active part in the work on domestic unmanned aerial vehicles.

Our activity is not limited only to the aviation area. We were actively working on ensuring aeroelastic stability of bridges. Thus, at the end of the year we completed testing in the T- 103 tunnel of models of two parallel road bridges over the Don River near Aksai town (Rostov region). The experiment showed that the mutual influence of two adjacent bridges is quite high. At a wind speed of 18-20 m / s, intense vibrations of the windward bridge can occur, reaching amplitudes of 300-400 mm, which exceeds the level of comfort human perception of vibrations and can even cause structural damage to the bridge. We recommended the builders to use the standard “soundproof” screens at both outer side ends of the longest spans of both bridges, as well as install special “dynamic dampers” in these bays that increase vibrations decrement of the bridge structure.

I must say that after the issue with wind-induced vibrations of the Volgograd Bridge, the interest in our research and its importance grew. Now the relevant requirements are established in building codes. In this connection, the demand for research of elastic vibrations of structures in wind flow has increased and our “aviation” techniques and experiment technologies are very useful.

Does TsAGI hold a monopoly in this market, or we have competitors?

You know, today there are very few monopolies in the world. But, nevertheless, in Russia we are somewhat monopolists, because we can very quickly and efficiently design and manufacture models, conduct experiments in wind tunnels, we have a lot of experience and a database. I don’t know any other Russian organizations that could perform the same work at our level. A composite model must be created. This work is successfully performed by our laboratory, which actively uses prototyping technology. Our experts quickly manufacture quality bridge models identical in dynamic characteristics, imitating the smallest detail, to give correct recommendations for securing the bridge structure, both at the construction phase and the operational phase.

How’s the work going on in helicopter and aerospace areas?

We have prepared a report on the perspective high-speed helicopter vibrations and loads. We cooperate with Mil, KVZ and Kamov companies regarding helicopter operation safety. This year, we approved about 280 conclusions related to operation of fuselages and helicopter blades and maintaining their operating life.

As to the aerospace area, for example, we are currently preparing for vibroacoustic strength testing of telemetry units of the RK-1500 launching assembly. The tests will be held next year. We are preparing for modernization of the chamber in the near future, as the unit is already quite obsolete. Also speaking about space subject, substantive talks have been recently held with Lavochkin Design Bureau, and perhaps new collaborations are to be expected.

Please, tell us about the participation of the Aircraft Strength Complex in international projects in 2013

Currently, international projects are very important to us. Global science evolves very fast, and we need to know what is happening and who is doing what in the area of our expertise.

In 2013 I would note a major conference on mesh structures strength held as a part of MAKS and successful completion of the international project “Alaska.” Since the results were successful, a new project has been launched called “Polar Bear,” relating to integrated assessment of the fuselage mesh structures characteristics and aimed at bringing the concept to the next level of technological readiness.

We completed a very interesting contract with Embraer, where our experts designed, manufactured and tested in transonic wind tunnel an aeroelastic model of the prospective passenger aircraft wing. Our young specialists were actively involved in the work. The team of researchers was delivering the work in Brazil, where they had a good international experience.

We took part in international conferences. In particular, in June in the UK (Bristol), an international IFASD forum on aeroelasticity and structural dynamics was held, where our experts made ​​several presentations. It is very important and well-known specialized conference. It was decided to hold the next forum in 2015 in St. Petersburg, where TsAGI will be the main organizer on the part of Russia.

Do you have something to say about Russian conferences?

It is very important for us that in 2012, TsAGI resumed the practice of holding conferences on aircraft strength. Together with colleagues from other institutes and organizations, we agreed that such conferences will be held once every two years. In 2013 abstracts of the conference were published, and we began to prepare for the next one. In 2014, again we plan to gather aircraft strength professionals under the roof of TsAGI. Of course, we participate in other conferences in Russia.

Composites are addressed not only in foreign projects, but also in domestic ones, including as a part of FTP. Isn’t there a duplication of work?

The truth is that the use of composites in aircraft is a very extensive work. Successful advancement in this area requires many issues to be resolved. The problems associated with the introduction of composites in the structure include development of materials, creation of designs that employ positive characteristics of composites in the best way, as well as manufacturing technologies, structural strength issues, computation and testing techniques and specifics, production and quality control issues affecting the strength, approaches to certification and operational behavior of structures. That is, it is a very wide range of problems, and it is impossible to cover all these in a single project. Each project addresses a specific range of issues, and when it’s all added together....

And when it’s all added together?

General knowledge and technology are summed up in the aviation industry. We hold workshops in our departments, and if complex question arises, we hear it at the general complex workshop. A large problem should be addressed in parts; this applies to the composite problem. All this knowledge is collected within the aircraft, which is created using all the technologies. Fighting contradictions and search for optimal solutions — this is the usual way to create aircraft structures. We tend to have natural contradictions between high aerodynamics and required strength, between weight efficiency and strength. And here we need the optimal solution which, on the one hand, allows creation of a competitive structure while on the other hand provides the necessary level of safety and environmental friendliness.

Does the TsAGI experimental base have enough capabilities to perform the entire complex of composite structures research?

Our Institute in general and the Aircraft Strength Complex in particular traditionally have developed comprehensive experimental bases. We have all the necessary competences to carry out static strength tests, frequency domain testing of aircraft, resource fatigue testing, and flutter research. Now our climatic base has launched and its active use is being started; acoustic strength testing is performed. That is, the core competencies of TsAGI associated with strength testing are implemented on the TsAGI’s site. Also, of course, we have colleagues: strength professionals in SibNIA, CIAM, GosNIIPAS etc. We have plans to build new strength test laboratory facilities, focused on multidisciplinary testing of structures including UAVs. But this is for the future.

What is your opinion on the work carried out during 2013, and plans for the future.

I think that has been a very busy and fruitful year; we have advanced significantly in all positions that were planned, and created a backlog for work in the years to come. Of course, we have a lot of plans and hopes for new research results related to FTP activities and creation of technological advances. Talking about specific projects, it’s going to be very difficult and important year in terms of promoting the MS-21 project (Yak- 242). We have prepared test benches and are waiting for tests of structural elements, composite and metal ones, with actual dimensions, manufactured using series production technologies. The IL-476, T-50 projects work will go forward as well, along with the work for the development of the Superjet aircraft family, and much more.

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